This website has been extremely helpful, but I question the integrity of the dates displayed. Most identify the source of the dates as either "assumed" or "based on other information". Here's what I'm finding:

In my U.S. research I discovered that my great-grandmother's(Catherine) maiden name was Cavanaugh (Kevane) and that they came from Kerry. I found out that Catherine and John McDonnell had 5 kids Michael, Patrick, Catherine, Margaret and Ellen. I found only one marriage record for John McDonnell and Catherine Kevane for 1850 (Ballyferriter), but found the baptism records for Catherine, Margaret and Patrick in the same Parish with parents John and Catherine Kevane, but their birth dates were 1838, 1843 and 1846. Those dates are all off by 6-8 years compared to the US records. I then found baptism records for Michael and Ellen in a different parish (dingle) with the same 1854 date, which is close to what I have for Michael in US, but 4 years off for Ellen.

Before I dismiss these records, I wanted to see if anyone else has encountered issues with the dates on this site. If these are the only ones listed on the site with the appropriate names and its not them, can I assume they were not registered with a church?